Orthopedic implant in the form of a plate to be fixed between two bone parts

ABSTRACT

The invention relates to a plate ( 1 ) fixed between two bone parts by means of screws engaged in holes ( 1   b ) formed in the thickness of said plate. The plate ( 1 ) comprises a rib which is inclined according to an angle of between 30° and 60° in relation to the plane defined by the plate and has a hole ( 1   a   1 ) for engaging a screw ( 2 ). Said rib is located in the central part of the width, over a determined part of the length of the plate so that the screw ( 2 ) brings the two bone parts into the compressive position.

The invention relates to the technical field of orthopedic implants.

More particularly, the invention relates to a plate for arthrodesis orosteosynthesis adapted to be fixed between two bone parts.

In a manner known to one having ordinary skill in the art, this type ofplate generally has holes for engaging screws, allowing arthrodesisbetween two bones or osteosynthesis between two bone fragments. This is,for example, the case for bones of the hand or foot, without howeverexcluding other applications, particularly in the field of the spine.Depending on the pathology to be treated, these plates can have ageneral rectilinear or other geometric shapes.

From this state of the art, one of the objects the invention proposes toattain is to improve, in a sure and efficient manner, compression in aprecise direction between the bone parts subjected to the plate.

To attain the given object to enhance the compression between the tworelative bone parts, according to the invention, the plate has aformation that orients at least one screw at an angle with respect to aplane defined by the plate, the angle being between about 30° and 60°.

According to an advantageous embodiment, the formation is a tab that isangled according to an angle between 30° and 60°, and having a hole forengaging the screw. The angled tab results from a cut out and adeformation of a portion of the plate.

In another embodiment, the formation is a hole angled at an anglebetween 30° and 60° for engaging the screw.

Considering the problem to be solved, the formation is located on adetermined portion of the length of the plate so that the screw ensuresthe compression of the two bone parts.

The invention is described hereinafter in more detail, with reference tothe attached drawing in which:

FIG. 1 is a perspective view of an embodiment of the plate;

FIG. 2 is a side view of the plate;

FIGS. 3 and 4 are perspective views showing the mounting of the platebetween two bone parts and their orientation by means of the plateaccording to the invention, the bone parts being shown schematically.

According to the invention, the plate 1 has at least one formation 1 aadapted to enable the positioning of at least one screw 2, at an angle aof between 30° and 60° with respect to a plane of the plate (FIG. 2).

In one embodiment, the formation la is an angled tab cut out anddeformed from the plate. For example, the deformation is made with acutting-punching operation. This angled tab has a hole 1 a 1 for a screw2. The angled tab 1 a is positioned along the length of the plate sothat after the screw 2 is fitted to it, the screw ensures thecompression together of the two bone parts, as indicated below in thedescription.

In another embodiment, to allow for an angular orientation of the screw2 according to an angle between about 30° and 60° , the formation 1 acan be formed as an angled hole. It must be noted that the tab 1 aenables adaptation of the angle as a function of the pathology to betreated, given that it is possible to deform this tab at will. In otherwords, the angle can be adjusted over a few degrees by the surgeon inthe operating room, using an appropriate tool.

With reference to FIGS. 3 and 4 that show the positioning of the plate 1between two bone parts O1 and O2:

-   -   Once the osteotomies have been carried out, a template of the        plate, which does not have a guide formation, enables the        position of this tab to be determined.    -   After determining the position of the tab, the surgeon makes a        corresponding recess with the appropriate rasp.    -   Once the plate having the tab has been positioned, the surgeon        sets one or two screws 3, on a side of the site of the        osteosynthesis of the arthrodesis toward the tab. A temporary        fastening pin can, possibly, be positioned in an complementary        lug.    -   The screw 2 is then engaged in the hole 1 a 1 of the tab 1 a to        place the fracture in compression.    -   Once the compression has been done, the surgeon can screw one or        several other additional fastening screws 3 and remove the        temporary pin.

In a known manner, this plate 1 has smooth and/or threaded holes for thefastening screws 3 set in the bone parts O1 and O2 to engage in, asshown in FIGS. 3 and 4.

Similarly, the plate 1 can have at least one hole 1 c for a pin fortemporarily positioning the plate 1. Advantageously, the plate 1 canhave a guide 1 c for the insertion of a pin on the side of one of thebone parts O1 and another guide 1 d for the insertion of another pin onthe side of the other bone part O2.

Considering the effect of the desired compression, such as indicatedabove, the guide 1 c is a circular hole whose diameter correspondssubstantially to that of the pin 4, whereas the other guide 1 d can bean elongated slot.

These provisions thus enable the bone to slide under the plate 1 as thescrews are set, while ensuring compression along a precise direction,generally axially or parallel to the plate. The pins are of any knownand appropriate type, and perfectly known to one having ordinary skillin the art.

The plate 1 can have several shapes, so that the holes 1 a in particularcan be aligned or arrayed, all or in part, according to the corners of atriangle or of a quadrilateral. These provisions, in triangle or inquadrilateral, of the screws, improve the stability of its mounting.

It must be noted also that the plate 1, no matter its shape, can belongitudinally bent so as to adapt to the curvature of the bone,consequently enabling the screws 2 to form an angle between them.

The advantages are readily apparent from the description.

1. An orthopedic implant in the form of a plate adapted to be fixedbetween two bone parts by screws engaged in throughgoing holes, whereinthe plate has a formation that is set at an angle between 30° and 60°with respect to a plane defined by the plate and having a hole forreceiving a screw, the formation being located in a transversely centralportion along the length of the plate such that the screw compressestogether the two bones parts.
 2. The implant according to claim 1,wherein the plate has a hole for the insertion of a pin on the side ofone of the bone parts and a hole for the insertion of a guide pin on theside of the other bone part.
 3. The implant according to claim 2,wherein one of the holes is a circular hole whose diameter correspondssubstantially to that of the pin, whereas the other hole is an elongatedslot.
 4. The implant according to claim 1, wherein the plate has smoothand/or threaded holes adapted to receive screws for fastening with thebone parts.
 5. The implant according to claim 4, wherein the holes arealigned.
 6. The implant according to claim 4, wherein some of the holesare arrayed at corners of a triangle or of a quadrilateral.
 7. Anorthopedic implant for joining two bone parts that are longitudinallyjuxtaposed, the implant comprising: a plate extending along a plateplane, formed with a plurality of anchor holes extending transversely ofthe plate plane through the plate, and adapted to lie against the boneparts with the plate plane extending longitudinally of the bone partsand bridging the bone parts and with at least one of the anchor holes toeach side of the fusion plane; anchor screws engaged generallyperpendicular of the plate plane through the anchor holes in the plateplane for securing the plate to both of the bone parts; a formation onthe plate forming a guide extending along an axis that, when the plateis lying against the two bone parts, extends from one of the bone partsinto the other of the bone parts; and a compression screw fittablethrough the formation and extending along the axis, whereby thecompression screw can longitudinally compress the two bone partstogether.
 8. The orthopedic implant defined in claim 7 wherein the twobone parts meet at a fusion plane generally perpendicular to the plateplane when the plate is lying against the bone parts, the axis extendingthrough the fusion plane.
 9. The orthopedic implant defined in claim 7wherein the formation is a tab unitarily formed with the bone plate andlying on a tab plane extending at an acute angle to the plate plane. 10.The orthopedic implant defined in claim 9 wherein the angle is betweenabout 30° and 60°.
 11. The orthopedic implant defined in claim 9 whereinat least one of the holes in the plate is formed as an elongated slot.12. The orthopedic implant defined in claim 11 wherein the slot isjuxtaposed with the other bone part when the plate is lying against thebone parts, whereby the plate can slide limitedly relative to the otherbone part when the compression screw is tightened.